Can't change the contents of a field

This is weird. I can change the contents of a field in the psql command prompt, but I can't do it in Microsoft Access via ODBC. Everytime I try to change a field in Microsoft Access, it first says: "ODBC--update on a linked table 'test' failed". Then it goes on to say:

"Error while executing the query; ERROR: Unable to identify an operating '=' for types 'xid' and 'int4'. You will have to retype this query using an explicit cast. (#1)".

Does anyone know why I can't change the field? I turned off the "read only" property. I am using Postgres 7.02 with the new 6.5 version of the ODBC drive (psotdrv.exe)

- Steve